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\l V. — Observations on the Young of a Species of Ixodes from 

 Brazil. By George Busk, Esq. 



Read April 27, 1842. 



At the last meeting of the Society, I presented some small living 

 Acari which I had received from Rio Janeiro. They came inclosed 

 in a letter, and had been sixty or seventy days on their passage, but 

 were then, and still are living. They were sent to me as specimens 

 of an insect called by the Brazilians, the Carapato, and which was 

 stated to be the cause of great mortality among the cattle in those 

 countries, and very troublesome to travellers, by the great irritation 

 and annoyance they produce. Since then I have been enabled, by 

 the kindness of a gentleman who was long resident in Brazil, and 

 who had suffered much by loss of cattle caused by this troublesome 

 insect, to collect additional information about it. I submitted que- 

 ries, to which he has furnished the following replies. 



1. The name of carapato or carapat is given to the insect, in con- 

 sequence of its resemblance to the seed of the Ricinus, which has 

 that name in Portuguese. 



2. It is common in all parts of South America where cattle abound. 



3. It infests cattle, horses, dogs and sheep. 



4 It is not found on plants ; and cattle generally become infested 

 with it when feeding in open and exposed pastures, where the sun's 

 heat is great ; and it increases most in dry seasons. 



It is generally supposed that the insect was not seen in the Brazils 

 previously to an excessively hot and dry summer, about 1824 or 25, 

 since which it has multiplied amazingly. It is remarkable that cattle 

 feeding in shady pastures and coppices, are frequently quite free from 

 the carapato, but will acquire it by infection from others. 



5. The mode in which it appears to cause destruction to the ani- 

 mal infested by it, is by the incessant irritation which prevents the 

 animal feeding or resting, and in consequence it becomes worn out. 



6. They first appear on those parts of the skin uncovered by hair, 

 and are then not larger than a pin's head, and make the part quite 

 black by their numbers. They adhere so closely, that scraping them 

 off would tear up the skin. In a short time they increase to the size 

 of a bean, or common tick, as seen in dogs, and fix themselves pro- 

 miscuously on all parts of the hide, where covered with hair. 



